3 Answers

You'll need to wait until Apple offers them as an option or a repair part. You have other options like adding a SSD as a second drive or putting in a hybrid drive like Seagate's Hybrid HD and from what I'm hearing a lot cheaper than a Fusion drive will cost.

It was expected Apple had a single device which had the two elements together as it turns out a fusion drive is nothing but two devices (HD & SSD) which are fused together as one logical volume via software. So you don't need any special Apple hardware to achieve the same function.

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